The word origionated with Mr.T. Due to the extended contact with cheap substitute gold, he can no longer tell the difference between anybody he meets. In order to save himself the humiliation of asking who he's talking to, he simply refers to anyone and every one as 'foo' or 'sucka'.

foo A sample name for absolutely anything,
especially programs and files (especially scratch files).
First on the standard list of metasyntactic variables used
in syntax examples.

The terms foobar, foo, bar, and baz are sometimes used as placeholder names (also referred to as metasyntactic variables) in computer programming or computer-related documentation. They have been used to name entities such as variables, functions, and commands whose purpose is unimportant and serve only to demonstrate a concept. The words themselves have no meaning in this usage. Foobar is sometimes used alone; foo, bar, and baz are sometimes used in that order, when multiple entities are needed.